With his team, he fashioned a series of doughnut-shaped silk scaffolds that slot together concentrically to mimic the layered structure of the brain. They seeded these with rat neurons and dunked them in collagen to encourage the cells to grow.

Advertisement

The neurons formed 3D networks that behaved a lot like a real brain, despite the structure and order imposed by the silk scaffold. “The scaffold makes it easier to probe different regions and functions in the tissue,” says Kaplan.

Juergen Knoblich at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences, who last year grew tiny human “brains” in the lab, says the work is another step towards understanding the function of neural networks.

This includes understanding how the networks function when they are damaged. Kaplan and his colleagues have experimented with dropping 11 gram weights onto their silk brain models and recording the response. They found that neurons in the silk brain entered a 2-minute-long period of hyperactivity after the injury. EEG readings from animals with brain injuries show similar patterns of neuronal hyperactivity, suggesting the silk brain model could help us understand exactly how traumatic brain injuries affect neurons and neural networks.

“Since the 3D brain system responds with markers one would expect, we have a start on how to use the system to study the nature of the damage and the best modes of treatment,” says Kaplan.